Abrasive pad, method and metal mold for manufacturing the same, and semiconductor wafer polishing method

ABSTRACT

An abrasive pad capable of transmitting light for end point detection without reducing polishing efficiency in the polishing of a semiconductor wafer using an optical end-point detection device, method of manufacturing the abrasive pad, a metal mold for manufacturing the abrasive pad, and a method of polishing a semiconductor wafer.  
     This abrasive pad comprises an abrasive substrate and a light transmitting member. The light transmitting member comprises a crosslinked polymer such as crosslinked 1,2-polybutadiene and a water-soluble substance such as β-cyclodextrin dispersed in the crosslinked polymer. Since the light transmitting member and the abrasive substrate are fused together as an integrated unit, slurry does not leak to the rear side of the abrasive pad during the abrasive pad used. This manufacturing method comprises setting the light transmitting member in the metal mold for insert molding and crosslinking a matrix dispersion for forming the abrasive substrate in this mold. The polishing method using this abrasive pad employs an optical end-point detection device.

FIELD OF THE INVENTION

[0001] The present invention relates to an abrasive pad, a method and ametal mold for manufacturing the same, and a semiconductor waferpolishing method.

[0002] More specifically, it relates to an abrasive pad which cantransmit light without reducing polishing efficiency, a method ofmanufacturing the abrasive pad, a metal mold for manufacturing theabrasive pad, an abrasive laminated pad which can transmit light, and asemiconductor wafer polishing method.

[0003] The present invention is used to polish a semiconductor wafer,making use of an optical end-point detection device.

DESCRIPTION OF THE PRIOR ART

[0004] In the polishing of a semiconductor wafer, after the purpose ofpolishing is accomplished, the decision of the polishing end point forterminating polishing can be made based on a time obtained empirically.However, various materials are used to form surfaces to be polished andpolishing time differs by each material. It is conceivable that thematerial forming the surface to be polished will change in the future.Further, the same can be said of slurry used for polishing and apolishing machine. Therefore, it is extremely inefficient to obtainempirically the each polishing time from the various polishings. To copewith this, research into optical end-point detection device and processusing an optical method capable of directly observing the state of thesurface to be polished is now under way (JP-A 9-7985, JP-A2000-326220and JP-A11-512977) (the term “JP-A” as used herein means an “unexaminedpublished Japanese patent application”).

[0005] In the optical end-point detection device and process, a windowwhich is made from a hard and homogeneous resin capable of transmittinglight for end-point detection and has substantially no ability to absorband carry a slurry substance is generally formed in an abrasive pad, andthe surface to be polished is observed only from this window (JP-A11-512977).

[0006] However, since the window has substantially no ability to holdand discharge slurry in the above abrasive pad, it is apprehended thatthe polishing efficiency of the abrasive pad may be reduced or becomenonuniform by forming the window. Therefore, it is difficult to form alarge ring window or to increase the number of windows.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention which has solved theabove problem to provide an abrasive pad which can transmit light forend-point detection without reducing polishing efficiency in thepolishing of a semiconductor wafer, a method of manufacturing theabrasive pad, a metal mold for manufacturing the abrasive pad, anabrasive laminated pad, and a semiconductor wafer polishing method.

[0008] Other objects and advantages of the present invention will becomeapparent from the following description.

[0009] The inventors of the present invention have studied an abrasivepad used for polishing, making use of an optical end-point detectiondevice, and have found that when a light transmitting member havinglight transmission properties is used as a window in place of a priorart window made from a hard and homogeneous resin which has no abilityto hold and discharge slurry, satisfactory light transmission propertiescan be ensured and further that the polishing end point can be detected.They have also found that when a water-soluble substance is dispersedand contained in the matrix material of the window, the window isprovided with the ability to hold and discharge slurry at the time ofpolishing. Further, they have discovered that slurry does not leak fromthe polishing surface when an abrasive substrate and a lighttransmitting member are fused and fixed together.

[0010] That is, according to the present invention, firstly, the aboveobjects and advantages of the present invention are attained by anabrasive pad comprising an abrasive substrate having a polishing surfaceand a light transmitting member which is fused to the abrasive substrateand comprises a water-insoluble matrix material and a water-solublesubstance dispersed in the water-insoluble matrix material.

[0011] According to the present invention, secondly, the above objectsand advantages of the present invention are attained by a method ofmanufacturing the abrasive pad of the present invention, comprisingholding a previously formed light transmitting member for an abrasivepad at a predetermined position in the cavity of a metal mold for insertmolding and injecting the material of an abrasive substrate into theremaining space in the cavity to fuse the light transmitting member tothe abrasive substrate.

[0012] According to the present invention, thirdly, the above objectsand advantages of the present invention are attained by a method ofmanufacturing the abrasive pad of the present invention, comprisingholding a previously formed abrasive substrate having a hole foraccepting a light transmitting member in the cavity of a metal mold forinsert molding and injecting the material of the light transmittingmember into the hole for accepting the light transmitting member to fusethe abrasive substrate to the light transmitting member.

[0013] According to the present invention, in the fourth place, theabove objects and advantages of the present invention are attained by ametal mold for insert molding for the manufacture of the abrasive pad ofthe present invention, which has a projection portion(s) and/or adepressed portion(s) for holding a light transmitting member or anabrasive substrate for an abrasive pad in a cavity.

[0014] According to the present invention, in the fifth place, the aboveobjects and advantages of the present invention are attained by anabrasive laminated pad comprising the abrasive pad of the presentinvention and a base layer having light transmission properties formedon the rear surface opposite to the polishing surface of the abrasivepad.

[0015] According to the present invention, in the sixth place, the aboveobjects and advantages of the present invention are attained by anabrasive laminated pad comprising the abrasive pad of the presentinvention, a base layer formed on the rear surface opposite to thepolishing surface of the abrasive pad, and a fixing layer for fixing thepad on a polishing machine, formed on the side opposite to the abrasivepad of the base layer.

[0016] According to the present invention, finally, the above objectsand advantages of the present invention are attained by a method ofpolishing a semiconductor wafer with an abrasive pad, characterized inthat the abrasive pad or the abrasive laminated pad of the presentinvention is used, and the polishing end point of the semiconductorwafer is detected by an optical end-point detection device through thelight transmitting member of the abrasive pad or the abrasive laminatedpad.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0018]FIG. 2 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0019]FIG. 3 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0020]FIG. 4 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0021]FIG. 5 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0022]FIG. 6 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0023]FIG. 7 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0024]FIG. 8 is a schematic diagram showing the shapes and fusion stateof an abrasive substrate and a light transmitting member;

[0025]FIG. 9 is a plan view of an example of the abrasive pad of thepresent invention;

[0026]FIG. 10 is a plan view of another example of the abrasive pad ofthe present invention;

[0027]FIG. 11 is a plan view of still another example of the abrasivepad of the present invention;

[0028]FIG. 12 is a partial sectional view of a metal mold for moldingthe abrasive pad of the present invention;

[0029]FIG. 13 is a sectional view showing that a light transmittingmember is fixed in a metal mold for molding an abrasive pad;

[0030]FIG. 14 is a sectional view showing that an abrasive substratedispersion is injected into a metal mold for molding an abrasive pad,having a light transmitting member fixed therein;

[0031]FIG. 15 is a sectional view of the abrasive pad of the presentinvention;

[0032]FIG. 16 is a partial sectional view of a metal mold having aprojection portion of the present invention;

[0033]FIG. 17 is a sectional view showing that an abrasive substrate isfixed in a metal mold for molding an abrasive pad, having a projectionportion;

[0034]FIG. 18 is a sectional view showing that a light transmittingmember dispersion is injected into a metal mold for molding an abrasivepad, having an abrasive substrate fixed therein;

[0035]FIG. 19 is a partial sectional view of a metal mold having adepressed portion;

[0036]FIG. 20 is a sectional view showing that an abrasive substratedispersion is injected into a metal mold for molding an abrasive pad,having a light transmitting member fixed therein;

[0037]FIG. 21 is a diagram of the abrasive pad of the present invention;

[0038]FIG. 22 is a diagram of an abrasive pad having fixing layers;

[0039]FIG. 23 is a diagram of an abrasive pad having a base layer;

[0040]FIG. 24 is a diagram of an abrasive pad having a base layer andfixing layers;

[0041]FIG. 25 is a diagram for explaining a polishing method using theabrasive pad or abrasive laminated pad of the present invention; and

[0042]FIG. 26 is a sectional view of a material to be polished suitablyby the polishing method of the present invention.

[0043]FIG. 27 is a diagram for showing a position of a through holeformed to an abrasive pad substrate in Examples 4 to 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The present invention will be described in detail hereinunder.

[0045] Abrasive Pad

[0046] The abrasive pad of the present invention comprises an abrasivesubstrate and a light transmitting member.

[0047] Abrasive Substrate

[0048] The abrasive substrate can hold slurry on the surface and canretain the residual dust after polishing temporarily. It doesn't matterwhether this abrasive substrate has light transmission properties ornot. The planar shape of the abrasive substrate is not particularlylimited and may be circular or polygonal (quadrilateral, etc.). The sizeof the abrasive substrate is not particularly limited as well.

[0049] Preferably, slurry can be held during polishing and the residualdust can be retained temporarily on the surface of this abrasivesubstrate. Therefore, the abrasive substrate may have at least onemember selected from minute holes (to be referred to as “pores”hereinafter), grooves and fluff formed by dressing. They may be formedin advance or formed at the time of polishing. That is, the abrasivesubstrate is selected from (1) an abrasive substrate which comprises awater-insoluble matrix material and a water-soluble substance dispersedin the water-insoluble matrix material, (2) an abrasive substrate(foamed material) which comprises a water-insoluble matrix material andpores dispersed in the water-insoluble matrix material, and (3) anabrasive substrate which consists only of a water-insoluble matrix(non-foamed material) and can be fluffed by dressing.

[0050] The material of the water-insoluble matrix in the above abrasivesubstrates (1) to (3) is not particularly limited and various materialsmay be used. It is preferably an organic material because it can beeasily molded to have a predetermined shape or properties and can beprovided with suitable elasticity. As the organic material may be usedvarious materials which are suitably used as the matrix material of theabrasive substrate to be described hereinafter.

[0051] The materials for forming the abrasive substrate may be the sameor different in type from the materials for forming the lighttransmitting member. An abrasive substrate made from materials differentin type from the materials for forming the light transmitting member oran abrasive substrate made from materials which are the same in type butdifferent in ratio from the materials for forming the light transmittingmember is preferably used.

[0052] To prevent the light transmitting member from projecting ordepressing at the time of polishing, it is preferred that the abrasionresistance of the abrasive substrate should not greatly differ from thatof the light transmitting member.

[0053] As the above “water-insoluble matrix material” (may also simplyreferred to as “matrix material” hereinafter), a thermoplastic resin,thermosetting resin, elastomer and rubber are preferably used alone orin combination.

[0054] Examples of the above thermoplastic resin include polyolefinresin, polystyrene resin, polyacrylic resin such as {(meth)acrylateresin}, vinyl ester resin (excluding acrylic resin), polyester resin,polyamide resin, fluororesin, polycarbonate resin and polyacetal resin.

[0055] Examples of the above thermosetting resin include phenolic resin,epoxy resin, unsaturated polyester resin, polyurethane resin,polyurethane-urea resin, urea resin and silicon resin.

[0056] Examples of the above elastomer include styrene elastomers suchas styrene-butadiene-styrene block copolymer (SBS) and hydrogenatedblock copolymer thereof (SEBS); thermoplastic elastomers such aspolyolefin elastomer (TPO), thermoplastic polyurethane elastomer (TPU),thermoplastic polyester elastomer (TPEE), polyamide elastomer (TPAE) anddiene elastomer (such as 1,2-polybutadiene); silicone resin elastomerand fluororesin elastomer.

[0057] Examples of the above rubber include butadiene rubber,styrene•butadiene rubber, isoprene rubber, isobutylene•isoprene rubber,acrylic rubber, acrylonitrile•butadiene rubber, ethylene propylenerubber, ethylene•propylene•diene rubber, silicone rubber and fluorinerubber.

[0058] The matrix material may be a crosslinked polymer ornoncrosslinked polymer. At least part of the matrix material ispreferably a crosslinked polymer. For example, the matrix material is amixture of two or more materials and at least part of at least one ofthe materials is a crosslinked polymer, or the matrix material is onlyone material and at least part of the material is a crosslinked polymer.

[0059] When at least part of the matrix material has a crosslinkedstructure, elastic recovery force can be provided to the matrixmaterial. Therefore, it is possible to suppress displacement caused byshearing stress applied to the abrasive pad at the time of polishing andto prevent the pores from being filled by the plastic deformation of thematrix material when it is excessively stretched at the time ofpolishing and dressing. It is also possible to prevent the surface ofthe abrasive pad from being fluffed excessively. Consequently, theretainability of slurry at the time of polishing is high, theretainability of slurry is easily recovered by dressing, and furtherscratching can be prevented.

[0060] Examples of the above crosslinked polymer include polymersobtained by crosslinking resins such as polyurethane resin, epoxy resin,polyacrylic resin, unsaturated polyester resin and vinyl ester resin(excluding polyacrylic resin), diene-based elastomer(1,2-polybutadiene), butadiene rubber, isoprene rubber, acrylic rubber,acrylonitrile-butadiene rubber, styrene-butadiene rubber,ethylene-propylene rubber, silicone rubber, fluorine rubber andstyrene-isoprene rubber, out of the above thermoplastic resins,thermosetting resins, elastomers and rubbers, and polymers obtained bycrosslinking polyethylene or polyvinylidene fluoride in the presence ofa crosslinking agent or through exposure to ultraviolet radiation orelectron beam. Ionomers may also be used.

[0061] These matrix materials may be used in combination of two or more.

[0062] Further, polymers modified by at least one hydrophilic functionalgroup such as acid anhydride group, carboxyl group, hydroxyl group,epoxy group or amino group to improve hydrophilic nature with slurry maybe used as the matrix material.

[0063] Examples of the above matrix material include polymers such asmaleic anhydride modified polyethylene, maleic anhydride modifiedpolypropylene, polybutadiene having a terminal hydroxyl group andpolybutadiene having a terminal carboxyl group; and polymers andcopolymers obtained by polymerizing a monomer having the abovefunctional group. Polybutadiene having a terminal hydroxyl group andpolybutadiene having a terminal carboxyl group are particularlypreferred. They may be used alone or in combination of two or more.

[0064] Further, the matrix material may be a mixture of a polymer havingany one of the above functional groups and a polymer having none of theabove functional groups.

[0065] The above “modification” may be carried out, for example, by (a)a method in which a polymer is heated in the presence of a monomerhaving an acid anhydride group and a peroxide (hydrogen peroxide,organic peroxide, etc.) to add a side chain having an acid anhydridestructure to a polymer having no acid anhydride structure in the mainchain, or (b) a method in which a polymer is heated in the presence of acompound having at least two acid anhydride structures in the molecularand/or a compound having an acid anhydride structure and a carboxylgroup in the molecular and a catalyst such as an acidic, alkali or metalcatalyst to add a side chain having an acid anhydride structure to apolymer having no acid anhydride structure in the main chain.

[0066] Examples of the monomer having an acid anhydride structure usedin the method (a) include maleic anhydride, itaconic anhydride,citraconic anhydride and endomethylenetetrahydrophthalic anhydride.

[0067] Examples of the compound having at least two acid anhydridestructures in the molecule used in the method (b) include pyromelliticanhydride and 3,3′, 4,4′-benzophenonetetracarboxyilc dianhydride; andexamples of the compound having an acid anhydride structure and carboxylgroup in the molecule include trimellitic anhydride.

[0068] The member constituting the above abrasive substrate may furthercomprise a water-soluble substance.

[0069] This water-soluble substance can form pores for holding slurryfor polishing by separating from the surface of the matrix material whenit contacts water. The average diameter of the pores formed after thewater-soluble substance separates from the abrasive pad, that is, theaverage diameter of the water-soluble substance contained in the matrixbefore it is eliminated may be 0.1 to 500 μm, preferably 0.5 to 100 μm,more preferably 5 to 50 μm.

[0070] The water-soluble substance includes what can be liberated whenit is gelled by contact to water, such as water absorbing resins, inaddition to water-soluble substances such as water-soluble polymers.This water-soluble substance may dissolve or gel in a medium containingwater as the main ingredient and methanol or the like. The water-solublesubstance is generally dispersed in the matrix material.

[0071] The water-soluble substance is often solid but may be liquid. Thesolid water-soluble substance is generally particulate but may befibrous such as whisker-shaped, other linear-shaped, or odd-shaped suchas tetrapod-shaped. The water-soluble substance is preferablyparticulate, more preferably solid particulate so that it can retain itsshape even at a thermal kneading temperature.

[0072] The average particle diameter of the water-soluble particles maybe 0.1 to 500 μm, preferably 0.5 to 100 μm, more preferably 5 to 50 μm.When this average particle diameter is smaller than 0.1 μm, the formedpores are small and an abrasive pad capable of holding abrasive grainscompletely may not be obtained. When the average particle diameter islarger than 500 μm, the mechanical strength of the obtained abrasive padmay lower. The average particle diameter is the average value of maximumlengths of the water-soluble particles contained in the matrix.

[0073] The water-soluble substance may be inorganic or organic. Out ofthese, it is preferably organic.

[0074] Examples of the organic water-soluble substance include dextrin,cyclodextrin, mannitol, saccharides such as lactose, celluloses such ashydroxypropyl cellulose and methyl cellulose, starch, protein, polyvinylalcohol, polyvinyl pyrrolidone, polyvinylsulfonic acid, polyacrylicacid, polyethylene oxide, water-soluble photosensitive resin andsulfonated polyisoprene. They may be used alone or in admixture of twoor more.

[0075] Examples of the inorganic water-soluble substance includepotassium acetate, potassium nitrate, potassium carbonate, potassiumhydrogencarbonate, potassium bromide, potassium phosphate, potassiumsulfate, magnesium sulfate and calcium nitrate. They may be used aloneor in admixture of two or more.

[0076] The liquid water-soluble substance is not limited to a particulartype but preferably what does not have a bad influence upon polishingefficiency when it dissolves in slurry during use. The liquidwater-soluble substance includes a water-soluble substance which isliquid itself and also a water-soluble substance which is not liquid butsolid at normal temperature and dissolves in water to become an aqueoussolution. Examples of the liquid water-soluble substance include organicacids such as formic acid, acetic acid, an aqueous solution of tartaricacid, aqueous solution of succinic acid and aqueous solution of malonicacid, and oxidizing agents such as aqueous solution of hydrogenperoxide, aqueous solution of peracetic acid and nitric acid.

[0077] When the water-soluble substance is contained in thewater-insoluble matrix material, it is dispersed in the entire matrixmaterial. Pores are formed in an abrasive pad comprising the matrixcontaining this water-soluble substance by the dissolution of thewater-soluble substance existent on the most surface layer of theabrasive pad through contact to water. The pores have the function ofholding slurry and retaining the residual dust after polishingtemporarily. The water-soluble substance dissolves or gels when itcontacts slurry which is an aqueous dispersion contained in the abrasivepad and separates from the matrix material.

[0078] Preferably, the water-soluble substance dissolves or gels inwater only when it is exposed to the surface layer of the abrasive padand does not absorb moisture or gel in the abrasive pad. Therefore, thewater-soluble substance preferably has an outer shell for suppressingmoisture absorption on at least part of its outer surface. This outershell may be physically adsorbed to or chemically bonded to thewater-soluble substance, or may be in contact with the water-solublesubstance by physical adsorption or chemical bonding. Examples of thematerial forming this outer shell include epoxy resin, polyimide,polyamide and polysilicate. Even when this outer shell is formed only onpart of the water-soluble substance, the above effect can be fullyobtained.

[0079] This water-soluble substance in the abrasive pad has the functionof increasing the indentation hardness of the abrasive pad (to 35 to 100in terms of Shore D hardness) in addition to the above function offorming pores. As this indentation hardness is high, pressure applied tothe surface to be polished by the abrasive pad can be increased.Therefore, not only the polishing rate can be improved but also highpolishing flatness can be obtained. Accordingly, this water-solublesubstance is particularly preferably a solid material which can securesufficiently high indentation hardness for the abrasive pad.

[0080] The content of the water-soluble substance in this abrasivesubstrate is preferably 90 vol % or less, more preferably 80 vol % orless, much more preferably 0.1 to 80 vol %, particularly preferably 1 to50 vol %, ideally 1 to 30 vol % based on 100 vol % of the total of thewater-insoluble matrix material and the water-soluble substance. Whenthe content of the water-soluble substance is higher than 90 vol %, itmay be difficult to completely prevent the water-soluble substancecontained in the matrix material from being gelled or dissolved oneafter another and therefore to maintain the hardness and mechanicalstrength of the abrasive pad at appropriate values.

[0081] The method of dispersing the above hydrophilic substance and thewater-soluble substance into the matrix material at the time ofproduction is not particularly limited. For instance, the matrixmaterial, hydrophilic substance and water-soluble substance andoptionally other additives are kneaded together to obtain a dispersion.The shape of the obtained dispersion is not particularly limited. Forexample, it is obtained in the form of a pellet, crumb or powder. Thematrix material is preferably kneaded under heating so that it can beeasily processed. At this heating temperature, the hydrophilic substanceand the water-soluble substance are preferably solid.

[0082] When they are solid, the hydrophilic substance is easilydispersed though it has compatibility with the matrix material and alsothe water-soluble substance is easily dispersed while it shows the abovepreferred average particle diameter. Therefore, the types of thehydrophilic substance and the water-soluble substance are preferablyselected according to the processing temperature of the used matrixmaterial.

[0083] Light Transmitting Member

[0084] The light transmitting member refers to a member for forming aportion having light transmission properties in part of the abrasivepad. A description is subsequently given of the light transmittingmember with reference to the accompanying drawings.

[0085] The shape of this light transmitting member is not particularlylimited. The planar shape of the light transmitting member on thepolishing surface side of the abrasive pad may be circular, elliptic,triangular, quadrilateral or polygonal. The sectional form perpendicularto the polishing surface of the light transmitting member is notparticularly limited. Any shape is acceptable if light can betransmitted between the polishing surface side and the non-polishingsurface side. For example, it may have sectional forms shown in FIGS. 1to 8. This light transmitting member 12 and the abrasive substrate 11are fused together as an integrated unit.

[0086] The term “fused” refers to a state in which the lighttransmitting member and the abrasive substrate are bonded together bymelting at least the bonding surface(s) of both or one of them withoutusing an adhesive. For the production of the abrasive pad, not only thebonding surface but also the entire light transmitting member may bemolten to be bonded, or the entire abrasive substrate may be molten tobe bonded.

[0087] The method of fusing together the light transmitting member andthe abrasive substrate is not particularly limited. For example, it maybe (1) an insert molding method in which one of the light transmittingmember and the abrasive substrate is held in a metal mold and the othermember is injected and fused, (2) a method in which the lighttransmitting member and the abrasive substrate are manufactured inpredetermined shapes and mated together, and their contact surfaces aremolten to be bonded together by infrared welding, high-frequencywelding, microwave welding or ultrasonic welding, or (3) a method inwhich a solvent is applied to the bonding surfaces of the lighttransmitting member and the abrasive substrate to bond them together.

[0088] Since the light transmitting member and the abrasive substrate ofthe abrasive pad of the present invention are fused together, there isno gap between the light transmitting member and the abrasive substrate,whereby slurry does not leak to the rear side of the abrasive pad.

[0089] The thickness of this light transmitting member may not besmaller than the thickness of the abrasive substrate as shown in FIGS. 1and 3, may be smaller than the maximum thickness of the abrasivesubstrate as shown in FIGS. 2, 4, 5, 6 and 8, or part of a lighttransmitting portion of the light transmitting member may be smaller inthe thickness as shown in FIG. 7.

[0090] To transmit light through the light transmitting member, theintensity of the light attenuates in proportion to the square of thethickness of the light transmitting member. Therefore, by reducing thethickness of the light transmitting member, light transmissionproperties can be greatly improved. For example, even when it isdifficult to obtain light having sufficiently high intensity for thedetection of an end point from this light transmitting member which hasthe same thickness as other portions of the abrasive pad used forpolishing making use of optical end-point detection, sufficiently highlight intensity can be ensured for the detection of an end point byreducing the thickness of the light transmitting member. The thicknessof the light transmitting member which has been made thin is preferably0.1 mm or more, more preferably 0.2 mm to 4 mm, much more preferably 0.3mm to 3 mm. When the thickness is smaller than 0.1 mm, it may bedifficult to secure sufficiently high mechanical strength for the lighttransmitting member.

[0091] A depressed portion, where the light transmitting member is notexistent, formed by reducing the thickness of the light transmittingmember (for example, a portion below the light transmitting member 12 inFIG. 2) or a depressed portion of the light transmitting member (forexample, a portion whose top, right and left sides are surrounded by thelight transmitting member 12 in FIG. 7) may be formed on either one ofthe front and rear sides of the abrasive pad. When it is formed on therear side of the abrasive pad, the thickness of the light transmittingmember can be reduced without affecting polishing efficiency.

[0092] The number of the light transmitting members is not particularlylimited and may be one or more. The position of the light transmittingmember is not particularly limited. For example, when the abrasive padhas one light transmitting member, it may be arranged as shown in theplan views of FIG. 9 and FIG. 10. Further, when the abrasive pad has twoor more light transmitting members, they may be arranged concentric toone another as shown in the plan view of FIG. 11.

[0093] As for the light transmission properties of the lighttransmitting member, when the thickness of the light transmitting memberis 2 mm, it preferably has a transmittance at a wavelength between 100and 3,000 nm of 0.1% or more or an integrated transmittance at awavelength between 100 to 3,000 nm of 0.1% or more. This transmittanceor integrated transmittance is more preferably 1% or more, much morepreferably 2% or more, particularly preferably 3% or more, ideally 4% ormore. The transmittance or integrated transmittance does not need to behigher than required, and may be 50% or less, preferably 30% or less,particularly preferably 20% or less.

[0094] In the abrasive pad used for polishing using an optical end-pointdetection device, the light transmitting member preferably has a hightransmittance at a wavelength range of 400 to 800 nm which is frequentlyused as light for end point detection. Therefore, it is preferable thata transmittance at a wavelength between 400 and 800 nm satisfies theabove requirements.

[0095] This transmittance is a value measured at each wavelength with anUL absorptiometer which can measure the absorbance of a 2 mm-thickspecimen at a predetermined wavelength. The integrated transmittance canbe obtained by integrating transmittances at a predetermined wavelengthrange measured similarly.

[0096] The “water-insoluble matrix material” (may be simply referred toas “matrix material” hereinafter) for forming the above lighttransmitting member is preferably a thermoplastic resin, thermosettingresin, elastomer, rubber or a combination thereof which can providelight transmission properties. Although this matrix material does notneed to be transparent or semitransparent if it has light transmissionproperties (which does not mean that it transmits only visible light),it preferably has higher light transmission properties, more preferablytransparency.

[0097] The thermoplastic resin, thermosetting resin, elastomer, rubber,etc. which can provide light transmission properties may be the same asthose listed for the water-insoluble matrix material used in the aboveabrasive substrate. These matrix materials may be used in combination oftwo or more. Further, the water-insoluble matrix material may be amixture of a polymer having a functional group and a polymer having nofunctional group as explained in detail for the above abrasivesubstrate.

[0098] Preferably, these matrix materials contain a hydrophilicsubstance having a functional group to improve its compatibility withthe water-soluble substance, abrasive grains, aqueous medium, etc. asrequired. What are enumerated for the above abrasive substrate may beused as the hydrophilic substance.

[0099] These hydrophilic substances may be used in combination of two ormore.

[0100] The matrix material may be a crosslinked polymer ornon-crosslinked polymer. At least part of the matrix material ispreferably a crosslinked polymer. For example, the matrix material is amixture of two or more materials and at least part of at least one ofthe materials is a crosslinked polymer, or the matrix material is onlyone material and at least part of the material is a crosslinked polymer.

[0101] When at least part of the matrix material has a crosslinkedstructure, elastic recovery force can be provided to the matrixmaterial. Therefore, it is possible to suppress displacement caused byshearing stress applied to the abrasive pad at the time of polishing andto prevent the pores from being filled by the plastic deformation of thematrix material when it is excessively stretched at the time ofpolishing and dressing. It is also possible to prevent the surface ofthe abrasive pad from being fluffed excessively. Consequently, theretainability of slurry at the time of polishing is high, theretainability of slurry is easily recovered by dressing, and furtherscratching can be prevented.

[0102] These crosslinked polymers are the same as those listed for theabove abrasive-substrate.

[0103] Out of these crosslinked polymers, crosslinked 1,2-polybutadieneis particularly preferred because it can provide sufficiently high lighttransmission properties, is stable to a strong acid or strong alkalicontained in many kinds of slurry and further is rarely softened bywater absorption. This crosslinked 1,2-polybutadiene may be blended withother rubber such as butadiene rubber or isoprene rubber. Further,1,2-polybutadiene may be used alone as the matrix material.

[0104] The residual elongation after breakage (to be simply referred toas “residual elongation at break” hereinafter) of the matrix material atleast part of which is a crosslinked polymer can be set to 100% or lesswhen a matrix material specimen is broken at 80° C. in accordance withJIS K 6251. This means that the matrix material has a total distancebetween bench marks of the specimen after breakage which is 2 times orless the distance between the bench marks before breakage. This residualelongation at break is preferably 30% or less, more preferably 10% orless, much more preferably 5% or less and 0% or more. As the residualelongation at break is higher than 100%, fine pieces scraped off fromthe surface of the abrasive pad or stretched at the time of polishing orsurface renewal tend to fill the pores.

[0105] The term “residual elongation at break” is an elongation obtainedby subtracting the distance between bench marks before the test from thetotal distance between each bench mark and the broken portion of thebroken and divided specimen in a tensile test in which a dumbbell-shapedspecimen No. 3 is broken at a tensile rate of 500 mm/min and a testtemperature of 80° C. in accordance with the “vulcanized rubber tensiletest method” specified in JIS K 6251. The test temperature is 80° C. asthe temperature reached by slide contact at the time of actual polishingis about 80° C.

[0106] The water-soluble substance is dispersed in the lighttransmitting member. It is a substance capable of forming pores by itscontact with an aqueous medium supplied from the outside at the time ofpolishing as described above.

[0107] The shape, size, content in the light transmitting member andmaterial of the water-soluble substance are the same as thewater-soluble substance described in detail for the above abrasivesubstrate.

[0108] Preferably, the water-soluble substance which is exposed to thesurface of the light transmitting member dissolves or gels in water andthe water-soluble substance which is contained in the light transmittingmember without surfacing does not absorb moisture or gel in the abrasivepad. Therefore, an outer shell made of an epoxy resin, polyimide,polyamide or polysilicate for suppressing moisture absorption may beformed on at least part of the outer surface of the water-solublesubstance.

[0109] This water-soluble substance has the function of matching theindentation hardness of the light transmitting member with that of otherportion of the abrasive pad in addition to the function of formingpores. The Shore D hardness of the entire abrasive pad is preferably 35to 100 in order to increase pressure to be applied at the time ofpolishing, improve polishing rate and obtain high flatness. However, itis often difficult to obtain a desired Shore D hardness only from thematrix material. In this case, the shore D hardness can be increased tothe same level as that of other portion of the abrasive pad bycontaining the water-soluble substance, besides the formation of pores.For this reason, the water-soluble substance is preferably a solidmaterial capable of securing sufficiently high indentation hardness forthe abrasive pad.

[0110] The method of dispersing the above hydrophilic substance and thewater-soluble substance in the matrix material at the time of productionmay be the same as the method described for the above abrasivesubstrate.

[0111] A compatibilizing agent such as a homopolymer, block copolymer orrandom copolymer modified by an acid anhydride group, carboxyl group,hydroxyl group, epoxy group, oxazoline group or amino group, which isoptionally added at the time of production to improve compatibilitybetween the matrix material and the water-soluble substance and thedispersibility in the matrix material of the water-soluble substance, anonionic surfactant and a coupling agent may be contained, in additionto the matrix material and the water-soluble substance.

[0112] At least one selected from an abrasive grain, oxidizing agent,polyvalent metal ion, organic acid, hydroxide or acid of an alkalimetal, pH modifier, surfactant and scratch prevention agent all of whichhave been contained in slurry may be contained in the abrasive pad ofthe present invention, that is, the light transmitting member and theabrasive pad substrate, in addition to the matrix material and thewater-soluble substance. Thereby, when this abrasive pad is used,polishing can be carried out by supplying only water. Further, to theabrasive pad of the present invention may be optionally added additivessuch as a filler, softening agent, antioxidant, ultraviolet lightabsorber, antistatic agent, lubricant and plasticizer in limits that donot impair the effect of the present invention.

[0113] Examples of the above abrasive grain include inorganic particlessuch as silica particle, alumina particle, ceria particle, zirconiaparticle and titania particle, organic particles such as polystyrene,and organic/inorganic composite particles such as polystyrene/silica.

[0114] The above oxidizing agent is not particularly limited if it iswater-soluble. Examples of the oxidizing agent include organic peroxidessuch as hydrogen peroxide, peracetic acid, perbenzoic acid andtert-butyl hydroperoxide, permanganic acid compounds such as potassiumpermanganate, bichromic acid compounds such as potassium bichromate,halogen acid compounds such as potassium iodate, nitric acid compoundssuch as nitric acid and iron nitrate, perhalogen acid compounds such asperchloric acid, transition metal salts such as potassium ferricyanide,persulfuric acid salts such as ammonium persulfate, salts of apolyvalent metal such as iron nitrate and cerium ammonium nitrate, andheteropoly-acids such as tungstosilicic acid, tungstophosphoric acid,molybdosilicic acid and molybdophosphoric acid. They may be used aloneor in combination of two or more. Out of these, hydrogen peroxide andorganic peroxides are particularly preferred because they do not containany elemental metal and their decomposed products are harmless. Bycontaining any one of these oxidizing agents, the polishing rate can begreatly improved when a metal layer such as a film to be processed of awafer is polished.

[0115] The content of the oxidizing agent may be 0 to 10 parts by mass(may be simply referred to as “parts” hereinafter), particularlypreferably 0 to 5 parts by mass based on 100 parts by mass of the wholepad as far as the effect of the present invention is not impaired.

[0116] Examples of the above polyvalent metal ion include ions of metalssuch as aluminum, titanium, vanadium, chromium, manganese, iron, cobalt,nickel, copper, zinc, germanium, zirconium, molybdenum, tin, antimony,tantalum, tungsten, lead and cerium. They may be used alone or incombination of two or more. The polyvalent metal ion is preferably anion of at least one metal selected from aluminum, titanium, chromium,manganese, iron, copper, zinc, tin and cerium because a high polishingrate can be obtained. Out of these, iron ion and copper ion areparticularly preferred. One or more out of nitrates, sulfates, acetatesand gluconates of aluminum, nitrates, sulfates, acetates and gluconatesof iron (III), and nitrates, sulfates, acetates and gluconates of copper(II) may be used as the metal salt(s) constituting the above polyvalentmetal ion. These iron nitrates (III) also serve as an oxidizing agent.The content of the polyvalent metal ion in the whole pad is 0 to 10% bymass, particularly preferably 0 to 5% by mass.

[0117] The above organic acid can stabilize the above oxidizing agentand further improve the polishing rate. Preferred examples of theorganic acid include paratoluenesulfonic acid, dodecylbenzenesulfonicacid, isoprenesulfnoic acid, gluconic acid, lactic acid, citric acid,tartaric acid, malic acid, glycolic acid, malonic acid, formic acid,oxalic acid, succinic acid, fumaric acid, maleic acid and phthalic acid.Out of these, gluconic acid, lactic acid, citric acid, tartaric acid,malic acid, glycolic acid, malonic acid, formic acid, oxalic acid,succinic acid, fumaric acid, maleic acid and phthalic acid arepreferred. Particularly preferred are tartaric acid, malic acid,succinic acid and phthalic acid. These organic acids may be used aloneor in combination of two or more. The content of the organic acid in thewhole pad is preferably 0 to 10% by mass, particularly preferably 0 to5% by mass.

[0118] The above surfactant may be cationic, anionic or nonionic.Examples of the cationic surfactant include aliphatic amine salts andaliphatic ammonium salts. Examples of the anionic surfactant includefatty acid soap, carboxylic acid salts such as alkyl ether carboxylates,sulfonic acid salts such as alkylbenzenesulfonates,alkylnaphthalenesulfonates and α-olefinsulfonates, sulfuric acid estersalts such as higher alcohol sulfuric acid ester salts, alkyl ethersulfates and polyoxyethylene alkylphenyl ethers, and phosphoric acidester salts such as alkyl phosphates. Examples of the nonionicsurfactant include ethers such as polyoxyethylene alkyl ethers, etheresters such as polyoxyethylene ethers of a glycerin ester, and esterssuch as polyethylene glycol fatty esters, glycerin esters and sorbitanesters. The content of the surfactant in the whole pad is preferably 0to 10% by mass, particularly preferably 0 to 5% by mass.

[0119] Examples of the above filler include materials which improvestiffness, such as calcium carbonate, magnesium carbonate, talc andclay, and materials having a polishing effect such as manganese dioxide,manganese trioxide and barium carbonate.

[0120] The abrasive pad of the present invention may have a fixing layer13 for fixing the abrasive pad on a polishing machine for polishing onthe rear surface opposite to the polishing surface as shown in FIG. 22.The fixing layer is not particularly limited if it can fix the abrasivepad itself.

[0121] This fixing layer may be a layer consisting of a layer formed byusing an adhesive double-coated tape, for example, an adhesive layer 131and a peel layer 132 formed on the outer surface of the adhesive layer131, or an adhesive layer 131 formed by applying an adhesive. The peellayer 132 may be formed on the outer surface of the adhesive layerformed by applying an adhesive.

[0122] The adhesive material for forming the fixing layer is notparticularly limited. It is, for example, a thermoplastic, thermosettingor photo curable acrylic adhesive or synthetic rubber adhesive.Commercially available products of the adhesive material include #442 of3M Limited and #5511 and #5516 of Sekisui Chemical Co., Ltd.

[0123] Out of these fixing layers, a layer formed by using an adhesivedouble-coated tape is preferred because it has a peel layer in advance.A fixing layer having a peel layer can protect an adhesive layer beforeuse and can easily fix the abrasive pad on the polishing machine byremoving the peel layer at the time of use.

[0124] The light transmission properties of the material of the fixinglayer are not particularly limited. When the material of the fixinglayer does not have light transmission properties or has low lighttransmission properties, a through hole may be formed at a positioncorresponding to the light transmitting member. This through hole may belarger or smaller than or the same as the area of the light transmittingmember.

[0125] It is preferred that a fixing layer should not be formed in thepath of transmitted light when a through hole is formed in the fixinglayer.

[0126] Further, when a fixing layer is formed by using an adhesivedouble-coated tape, a through hole can be formed at a predeterminedposition of the adhesive double-coated tape. The method of forming thisthrough hole is not particularly limited. The through hole may be formedwith a laser cutter or punching blade. When a laser cutter is used, thethrough hole may be formed after a fixing layer is formed by using anadhesive double-coated tape.

[0127] The above additives which have been contained in slurry may becontained in the whole abrasive pad of the present invention,particularly its abrasive substrate or light transmitting member. Otheradditives may further be contained. A groove or dot pattern may beformed on the polishing surface in a predetermined shape.

[0128] The planar shape of the abrasive pad is not particularly limitedand may be circular (disk-like) or polygonal such as quadrilateral(belt-like, roller-like). The size of the abrasive pad is notparticularly limited but may be 500 to 900 mm in diameter when it isdisk-shaped.

[0129] The method of manufacturing the abrasive pad of the presentinvention is not particularly limited but the abrasive pad of thepresent invention may be manufactured by using mainly the followingmetal mold for insert molding.

[0130] Metal Mold for Insert Molding

[0131] The metal mold for insert molding of the present invention has aprojection portion(s) and/or a depressed portion(s) for positioning thelight transmitting member or the abrasive substrate which is molded inadvance.

[0132] The position, shape, size and number of the projection portionsand/or depressed portions for positioning the light transmitting memberor the abrasive substrate are not particularly limited if they canposition the light transmitting member or the abrasive substrate.

[0133] As for the projection portion(s) for positioning the lighttransmitting member, (1) a plurality of, for example, 3 or 4 dot-like,point-like or prolonged projections are arranged to surround the lighttransmitting member as shown in FIG. 12 and FIG. 13, (2) the aboveprojections are each fitted in a depression formed in the center of thebottom of the light transmitting member, or (3) a ring-shapedprojection, partially ring-shaped projection or quadrilateralprojections, for example, prolonged projections are arranged to surroundthe light transmitting member in a ring-shaped or quadrilateral form sothat they are mated with the light transmitting member having a circularbottom or quadrilateral bottom. As for the projection portion(s) forpositioning the abrasive substrate, a disk-like or small quadrilateralpillar-like projection is fitted in a hole for accepting the lighttransmitting member in the abrasive substrate as shown in FIG. 16 andFIG. 17, or a dot-like, point-like or prolonged projection is fitted ina depression formed in the abrasive substrate.

[0134] Since the surface of the projection for fixing the abrasivesubstrate is a surface for forming the surface layer of the lighttransmitting member, the surface of the projection desirably hasexcellent flatness to improve the light transmission properties of thelight transmitting member. It is particularly preferably a mirror finishsurface.

[0135] As for the depressed portion(s) for positioning the lighttransmitting member, as shown in FIG. 19 and FIG. 20, a circular orquadrilateral depression is formed to be mated with the lighttransmitting member, or depressions are arranged to be mated withdot-like, point-like or prolonged projections formed in the lighttransmitting member.

[0136] Further, as for the depressed portion(s) for positioning theabrasive substrate, depressions are arranged to be mated with dot-like,point-like and prolonged projections formed on the bottom portion of theabrasive substrate.

[0137] Method of Manufacturing Abrasive Pad

[0138] The method of manufacturing the abrasive pad of the presentinvention is not particularly limited if the light transmitting memberor the abrasive substrate can be held in the metal mold and the materialfor forming the light transmitting member or the abrasive substrate canbe injected into the cavity. To facilitate the manufacture of theabrasive pad of the present invention, the above metal mold for insertmolding is preferably used.

[0139] This manufacturing method is mainly the following method (1) or(2).

[0140] (1) A dispersion is obtained by pre-kneading a matrix, awater-soluble substance and the like for forming the light transmittingmember. The obtained dispersion is molded in a metal mold having amolding cavity to manufacture the light transmitting member.

[0141] Then, this light transmitting member is set in a metal moldhaving a cavity and a dispersion for forming the abrasive substrate,obtained by kneading or the like, is injected and molded to obtain anabrasive pad.

[0142] The above method (1) will be described in detail with referenceto FIG. 13 to FIG. 15. The molded light transmitting member is heldbetween the projection portions of the metal mold for insert moldinghaving projection portions 721 for positioning as shown in FIG. 13.Thereafter, the metal mold 71 is fastened and the dispersion for formingthe abrasive substrate, obtained by kneading or the like, is injectedfrom an injection port (not shown) as understood from FIG. 14. Thisdispersion is solidified by cooling to mold an abrasive pad. Before theabove metal mold is fastened, the dispersion for forming the abrasivesubstrate may be directly injected and then the above mold 71 may befastened before molding.

[0143] Thereby, an abrasive pad having a sectional form shown in FIG. 15is obtained.

[0144] (2) An abrasive substrate having a hole for accepting the lighttransmitting member is first molded and then set in a metal mold havinga cavity, a dispersion for forming the light transmitting member,obtained by kneading or the like, is injected into the hole of theabrasive substrate and molded in the metal mold to manufacture the lighttransmitting member, thereby obtaining an abrasive pad. The above holemay be a hole having a bottom or a through hole without a bottom. Anabrasive substrate having a through hole is commonly used.

[0145] The above method (2) will be described with reference to FIG. 17.An abrasive substrate molded in a predetermined shape is held onto theprojection portion 721 of a metal mold for insert molding having aprojection portion for positioning as shown in FIG. 17. Thereafter, themold 71 is fastened and the dispersion for forming the abrasivesubstrate, obtained by kneading or the like, is injected from aninjection port (not shown) to be molded. Before the above mold isfastened, the dispersion for forming the abrasive substrate may bedirectly injected and the above mold 71 may be fastened to mold it.

[0146] The abrasive pad shown in FIG. 2 is thereby obtained.

[0147] In the above methods (1) and (2), the inside temperature of themetal mold for insert molding is preferably 30 to 300° C., morepreferably 40 to 250° C., much more preferably 50 to 200° C.

[0148] The height of the light transmitting member and the thickness ofthe abrasive substrate do not need to be the same. Further, they may beprocessed to a desired thickness with abrasive paper, et al.

[0149] By this insert molding method, abrasive pads having a complexsectional form as shown in FIGS. 1 to 8 can be easily manufactured. Theabrasive substrate and the light transmitting member can be firmly andeasily bonded together.

[0150] A groove or dot pattern may be formed in a predetermined shape onthe polishing surface of the abrasive pad of the present invention asrequired in order to facilitate the discharge of the used slurry. Whenthe groove or dot pattern is required, it can be obtained by forming adepression on the front side of the abrasive pad by reducing thethickness of the above light transmitting member.

[0151] Abrasive Laminated Pad

[0152] The abrasive laminated pad of the present invention comprises theabrasive pad of the present invention and a base layer formed on therear surface of the abrasive pad and has light transmission propertiesin the lamination direction.

[0153] The above “base layer” is a layer 81 formed on the rear surfaceopposite to the polishing surface of the abrasive pad as shown in FIG.23. It doesn't matter whether the base layer has light transmissionproperties or not. For example, a base layer made of a material havingthe same or higher light transmission properties than the lighttransmitting member is used to secure light transmission properties forthe abrasive laminated pad. In this case, a cut-away (through hole) maybe or may not be formed. Further, when a base layer having no lighttransmission properties is used, the light transmission properties ofthe abrasive laminated pad can be secured by cutting away part of thebase layer for transmitting light.

[0154] The shape of the base layer is not particularly limited and itsplanar shape may be quadrate, for example, quadrilateral, or circular.In general, it can be formed as a thin sheet. This base layer may be thesame in planar shape as the abrasive pad. When it has a cut-away portionfor securing light transmission, this portion is excluded.

[0155] The material for forming the base layer is not particularlylimited and various materials may be used. An organic material ispreferably used because it is easily molded to have a predeterminedshape and predetermined properties and can be provided with suitableelasticity. The same materials as those used as the matrix material ofthe above-described light transmitting member may be used as thisorganic material. The material for forming the base layer may be thesame or different from the matrix material(s) of the light transmittingmember and/or the abrasive substrate.

[0156] The number of the base layers is not particularly limited and maybe one or more. When two or more base layers are formed, they may be thesame or different. The hardness of the base layer is not particularlylimited but preferably lower than that of the abrasive pad. Thereby, theabrasive laminated pad has sufficiently high flexibility and suitableconformability to the unevenness of the surface to be polished as awhole.

[0157] The same fixing layers 131 and 132 as in the abrasive pad may beformed on the abrasive laminated pad of the present invention as shownin FIG. 24. They are generally formed on the rear surface of the baselayer of the abrasive laminated pad, that is, the surface opposite tothe polishing surface. They may be the same as that used in the aboveabrasive pad.

[0158] Further, the abrasive laminated pad is not limited to aparticular shape and may be the same in shape and size as above.

[0159] Method of Polishing a Semiconductor Wafer

[0160] The method of polishing a semiconductor wafer of the presentinvention is to polish a semiconductor wafer with the abrasive pad orabrasive laminated pad of the present invention, using an opticalend-point detection device for detecting the polishing end point of thesemiconductor wafer.

[0161] The above “optical end-point detection device” is capable ofdetecting the polishing end point of the surface to be polished fromlight reflected from the surface of an object to be polished bytransmitting light to the polishing surface through the lighttransmitting member from the rear surface side of the abrasive pad.Other measurement principles are not particularly limited.

[0162] In the method of polishing a semiconductor wafer of the presentinvention, the detection of an end point can be carried out withoutreducing polishing efficiency. For example, when the abrasive pad or theabrasive laminated pad, is disk-shaped, light transmitting members arearranged in a loop and concentric to the center of the disk so thatpolishing can be carried out while the polishing end point is alwaysmonitored. Therefore, polishing can be ended surely at the optimalpolishing end point.

[0163] In the method of polishing a semiconductor wafer of the presentinvention, a polishing machine shown in FIG. 25 may be used. That is,the machine comprises a rotatable base 2, a pressure head 3 which canturn and move in vertical and horizontal directions, a slurry feed unit5 which can drop a predetermined amount per unit time of slurry on thebase 2, and an optical end-point detection unit 6 installed below thebase 2.

[0164] In this polishing machine, the abrasive pad (including theabrasive laminated pad) 1 of the present invention is fixed on the base2, and the semiconductor wafer 4 is fixed to the lower end face of thepressure head 3 and pressed on the abrasive pad at a predeterminedpressure. Slurry is dropped on the base 2 from the slurry feed unit 5 ina predetermined amount each time, and the base 2 and the pressure head 3are turned to bring the semiconductor wafer in slide contact with theabrasive pad for polishing.

[0165] End-point detection radiation R₁ having a predeterminedwavelength or wavelength range from the optical end-point detection unit6 is applied to the surface to be polished of the semiconductor wafer 4from the back of the base 2 through the light transmitting member 11 forpolishing. That is, the base 2 itself has light transmission propertiesor the end-point detection radiation can be transmitted through acut-away portion of the base 2. Reflected radiation R₂ obtained byreflecting this end-point detection radiation R₁ from the surface to bepolished of the semiconductor wafer 4 is seized by the optical end-pointdetection unit 6 so that polishing can be carried out while the state ofthe surface to be polished is monitored from this reflected light.

[0166] The suitable material to be polished by the polishing method ofthe present invention is, for example, a laminated substrate having astructure shown in FIG. 26. This laminated substrate comprises asubstrate made of silicon et al, a fist insulating film made of siliconoxide et al, a second insulating film having a groove (insulatingmaterial is selected from TEOS oxide film (silicon oxide-basedinsulating film prepared by a chemical vapor deposition method usingtetraethoxysilane as raw material) insulating film having a lowdielectric constant (such as silsequioxane, fluorine added SiO₂,polyimide-based resin, benzocyclobutene, etc.), etc.), a barrier metalfilm and a metal film as a wiring material (pure copper film, puretungsten film, pure aluminum film, alloy film, etc.).

[0167] The object to be polished is, for example, an object to bepolished including a buried material, or an object to be polishedincluding no buried material.

[0168] The object to be polished including a buried material is, forexample, a laminate which comprises a desired material deposited by CVDor the like so that the desired material is buried in at least thegroove of a substrate which will become a semiconductor device (whichgenerally comprises at least a wafer and an insulating film formed onthe front surface of the wafer and may further comprise a stopper layeras a stopper for polishing formed on the insulating film) having agroove on at least its front surface. For the polishing of this objectto be polished, after the buried material deposited excessively isremoved by polishing with the abrasive pad of the present invention, thesurface thereof can be polished to be flattened. When the object to bepolished has a stopper layer under the buried material, the stopperlayer may be polished in the latter stage at the same time.

[0169] The buried material is, for example, (1) an insulating materialused in the STI (Shallow Trench Isolation) step, (2) at least one metalwiring material selected from Al and Cu used in the damascene step, (3)at least one via plug material selected from W, Al and Cu used in thestep of forming a via plug, or (4) an insulating material used in thestep of forming an interlayer insulating film.

[0170] The stopper material for forming the above stopper layer is anitride-based material such as Si₃N₄, TaN or TiN, or a metal-basedmaterial such as tantalum, titanium or tungsten.

[0171] The above insulating material is a silicon oxide (SiO₂) film, aboron phosphorus silicate film (BPSG film) which comprises SiO₂ andsmall amounts of boron and phosphorus, an insulating film called “FSG(Fluorine doped Silicate Glass)” formed by doping SiO₂ with fluorine, ora silicon oxide-based insulating film having a small dielectricconstant.

[0172] Examples of the silicon oxide film include a thermal oxide film,PETEOS film (Plasma Enhanced-TEOS film), HDP film (High Density PlasmaEnhanced-TEOS film) and silicon oxide film obtained by thermal CVD.

[0173] The above thermal oxide film can be formed by exposinghigh-temperature silicon to an oxidizing atmosphere and chemicallyreacting silicon with oxygen or silicon with water.

[0174] The above PETEOS film can be formed from tetraethyl orthosilicate(TEOS) by CVD making use of plasma as accelerating means.

[0175] The above HDP film can be formed from tetraethyl orthosilicate(TEOS) by CVD making use of high-density plasma as accelerating means.

[0176] The above silicon oxide film obtained by thermal CVD can beobtained by normal-pressure CVD (AP-CVD) or low-pressure CVD (LP-CVD).

[0177] The above boron phosphorus silicate film (BPSG film) can beobtained by normal-pressure CVD (AP-CVD) or low-pressure CVD (LP-CVD).

[0178] The above insulating film called “FSG” can be formed by CVDmaking use of high-density plasma as an accelerator.

[0179] Further, the above silicon oxide-based insulating film having asmall dielectric constant can be obtained by applying a raw material toa substrate by rotational coating or the like and heating it in anoxidizing atmosphere. Examples of the silicon oxide-based insulatingfilm include an HSQ film (Hydrogen Silsequioxane film) made fromtriethoxysilane and MSQ film (Methyl Silsequioxane film) containingtetraethoxysilane and methyl trimethoxysilane as one of its rawmaterials.

[0180] Insulating films having a small dielectric constant made from anorganic polymer such as polyarylene-based polymer, polyaryleneether-based polymer, polyimide-based polymer or benzocyclobutene polymerare also included.

[0181] This flush type laminate is shown in FIG. 26. That is, thelaminated substrate 9 comprises a substrate 91 made of silicon et al, aninsulating film 92 made of silicon oxide et al formed on the siliconsubstrate 91, an insulating film 93 formed of silicon nitride et alformed on the insulating film 92, an insulating film 94 made of PTEOS(material synthesized from tetraethoxysilane by CVD) formed on theinsulating film 93 to form a groove, a barrier metal film 95 made oftantalum et al formed to cover the insulating film 94 and the groove,and a film 96 (groove is formed on the surface which is uneven) made ofa wiring material such as metal copper formed on the above barrier metalfilm 95 to fill the groove.

[0182] The object to be polished including no buried material is asubstrate made of polysilicon, bare silicon et al.

EXAMPLES

[0183] The following examples are provided to further illustrate thepresent invention.

Example 1

[0184] (1) Manufacture of Light Transmitting Member

[0185] 97 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) and 3vol % of β-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded, a crosslinkingreaction was carried out in a press mold at 170° C. for 20 minutes tomold the kneaded product, and the molded product was cut to obtain alight transmitting member measuring 58 mm×21 mm×2.5 mm.

[0186] (2) Kneading of Abrasive Substrate Material

[0187] 80 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) whichwould be crosslinked later to become a matrix material and 20 vol % ofβ-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded.

[0188] (3) Manufacture of Abrasive Pad

[0189] The light transmitting member obtained in (1) above was setbetween the projection portions (721) of a metal mold for insert moldingas shown in FIG. 13, the remaining space in the cavity of the abovemetal mold was filled with the abrasive substrate material kneaded in(2) above, the metal mold (71) was fastened, and a crosslinking reactionwas carried out at 170° C. for 20 minutes to mold a disk-like abrasivepad having a diameter of 60 cm and a thickness of 2.5 mm.

[0190] (4) Evaluation of Abrasive Pad

[0191] The abrasive pad manufactured as described above had a Shore Dhardness of 70 and a tensile residual elongation of 2%.

[0192] This abrasive pad was mounted on the base of a polishing machineto polish a thermal oxide film water at a base revolution of 50 rpm anda slurry flow rate of 100 cc/min. When the polishing rate was measured,it was 980 Å/min.

[0193] The light transmitting member obtained in the above Example (1)was measured for its transmittance at a wavelength of 650 nm with a UVabsorptiometer (U-2010 of Hitachi, Ltd.). As a result, the averageintegrated transmittance of 5 times of measurement was 30%.

Comparative Example 1

[0194] 80 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) whichwould be crosslinked later to become a matrix material and 20 volt ofβ-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded, and acrosslinking reaction was carried out in a press mold at 170° C. for 20minutes to mold a disk-like abrasive pad having a diameter of 60 cm anda thickness of 2.5 mm.

[0195] This polishing rate of this abrasive pad was 1,010 Å/min.

Comparative Example 2

[0196] A commercially available foamed polyurethane abrasive pad (IC1010of Rodel Co., Ltd.; Rohm and Haas Electronic Materials) having no lighttransmission properties was designated as Comparative Example 2. Thepolishing rate of this abrasive pad was 950 Å/min.

[0197] It can be understood from comparison between the polishing rateof Comparative Examples 1 and 2 and the polishing rate of Example 1 thatthe abrasive pad of the present invention is by no means inferior to anabrasive pad having no light transmitting member in polishing rate.

[0198] Since the light transmitting member and the abrasive substrateare fused together in the abrasive pad of the present invention, slurrydoes not leak to the rear side of the abrasive pad while the abrasivepad is used and the optical end-point detection unit (6) shown in FIG.25 is not contaminated.

Example 2

[0199] (1) Manufacture of Light Transmitting Member

[0200] 95 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) and 5vol % of β-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 160° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 1.0part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded, a crosslinkingreaction was carried out in a press mold at 170° C. for 20 minutes tomold the kneaded product, and the molded product was cut to obtain alight transmitting member measuring 58 mm×21 mm×2.5 mm.

[0201] (2) Kneading of Abrasive Substrate Material

[0202] A mixture was prepared by dry blending 80 wt % of1,2-polybutadiene (JSR RB830 of JSR Corporation) with 20 wt % of astyrene-butadiene elastomer (JSR TR2827 of JSR Corporation). 70 volt ofthe mixture which would be crosslinked later to become a matrix materialwas kneaded with 30 volt of β-cyclodextrin (Dexy Pearl β-100 of BioResearch Corporation of Yokohama) as a water-soluble substance by adouble-screw extruder. Thereafter, dicumyl peroxide (Percumyl D of NOFCorporation) was added to the kneaded product in an amount of 0.8 partby mass based on 100 parts by mass of the total of 1,2-polybutadiene,styrene-butadiene elastomer and β-cyclodextrin and further kneaded.

[0203] (3) Manufacture of Abrasive Pad

[0204] The light transmitting member obtained in (1) above wasset-between the projection portions (721) of the metal mold for insertmolding as shown in FIG. 13, and the remaining space in the cavity ofthe metal old was filled with the abrasive substrate material kneaded in(2) above. The metal mold (71) was fastened, and a crosslinking reactionwas carried out at 170° C. for 20 minutes to mold a disk-like abrasivepad having a diameter of 60 cm and a thickness of 2.5 mm.

[0205] (4) Evaluation of Abrasive Pad

[0206] The abrasive pad manufactured as described above had a Shore Dhardness of 65 and a tensile residual elongation of 2%.

Example 3

[0207] A disk-like abrasive pad having a diameter of 60 cm and athickness of 2.5 mm was obtained in the same manner as in Example 1except that potassium sulfate (manufactured by Otsuka Chemical Co.,Ltd.) was used in place of β-cyclodextrin.

[0208] This abrasive pad had a Shore D hardness of 68 and a tensileresidual elongation of 2%.

Example 4

[0209] (1) Manufacture of Abrasive Pad Substrate

[0210] 80 vol % of 1,2-polybutadiene (JSR RB830 of JSR Corporation)which would be crosslinked later to become a matrix material and 20 voltof β-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded, and acrosslinking reaction was carried out in a press mold at 170° C. for 10minutes to obtain an abrasive substrate having a diameter of 820 mm. A59.4 mm×21.0 mm hole was made at a position 195 mm away from the centerof the molded product as shown in FIG. 27. In FIG. 27, “a” is thecentral point of the abrasive pad substrate and “b” is the central pointof the through hole formed to the central point of the abrasive padsubstrate.

[0211] (2) Kneading of Light Transmitting Member Material

[0212] 97 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) and 3volt of β-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded.

[0213] (3) Manufacture of Abrasive Pad

[0214] The abrasive pad substrate manufactured in (1) above was set ontothe projection portion (721) of the metal mold for insert molding asshown in FIG. 17 to ensure that the hole of the abrasive substrate wassituated at a position corresponding to the light transmitting member.

[0215] Further, the light transmitting member material kneaded in (2)above was injected into the space above the projection portion in thecavity of the metal mold, the metal mold (71) was fastened, and acrosslinking reaction was carried out at 170° C. for 20 minutes to moldan abrasive pad having a diameter of 820 mm in which the rear surface ofthe light transmitting member was recessed from the rear surface of theabrasive substrate.

[0216] (4) Evaluation of Abrasive Pad

[0217] This abrasive pad had a Shore D hardness of 70 and a tensileresidual elongation of 2%.

Example 5

[0218] (1) Manufacture of Abrasive Pad Substrate

[0219] A mixture was prepared by dry blending 80 wt % of1,2-polybutadiene (JSR RB830 of JSR Corporation) with 20 wt % of astyrene-butadiene elastomer (JSR TR2827 of JSR Corporation). 70 volt ofthe mixture which would be crosslinked later to become a matrix materialwas kneaded with 30 volt of β-cyclodextrin (Dexy Pearl β-100 of BioResearch Corporation of Yokohama) as a water-soluble substance by adouble-screw extruder. Thereafter, dicumyl peroxide (Percumyl D of NOFCorporation) was added to the kneaded product in an amount of 0.8 partby mass based on 100 parts by mass of the total of 1,2-polybutadiene,styrene-butadiene elastomer and β-cyclodextrin and further kneaded, anda crosslinking reaction was carried out in a metal mold for insertmolding having above light transmitting member at 170° C. for 20 minutesto mold an abrasive substrate having a diameter of 820 mm. A 59.4mm×21.0 mm hole was made at a position 195 mm away from the center ofthe molded product as shown in FIG. 27.

[0220] (2) Kneading of Light Transmitting Member Material

[0221] 97 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) and 3volt of β-cyclodextrin (Dexy Pearl β-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by akneader heated at 120° C. Thereafter, dicumyl peroxide (Percumyl D ofNOF Corporation) was added to the kneaded product in an amount of 0.8part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded.

[0222] (3) Manufacture of Abrasive Pad

[0223] The abrasive pad substrate manufactured in (1) above was set ontothe projection portion (721) of the metal mold for insert molding asshown in FIG. 17 to ensure that the hole of the abrasive substratemanufactured in (1) above was situated at a position corresponding tothe light transmitting member.

[0224] Further, the light transmitting member material kneaded in (2)above was injected into the space above the projection portion in thecavity of the metal mold, the metal mold (71) was fastened, and acrosslinking reaction was carried out at 170° C. for 20 minutes to moldan abrasive pad having a diameter of 820 mm in which the rear surface ofthe light transmitting member was recessed from the rear surface of theabrasive substrate.

[0225] (4) Evaluation of Abrasive Pad

[0226] This abrasive pad had a Shore D hardness of 70 and a tensileresidual elongation of 2%.

Example 6

[0227] After an abrasive pad was manufactured in the same manner as inExample 5, a double-tuck tape (Double Tuck Tape #512 of Sekisui ChemicalCo., Ltd.) essentially composed of foamed polyethylene was formed as abase layer on the non-polishing side of the abrasive pad. Further, a 60mm×23 mm through hole was made in the base layer at a positioncorresponding to the light transmitting member to secure lighttransmission properties.

Example 7

[0228] (1) Manufacture of Abrasive Pad Substrate

[0229] A mixture was prepared by dry blending 70 wt % of1,2-polybutadiene (JSR RB830 of JSR Corporation) with 30 wt % ofcommercially available polystyrene (HF55 of PS Japan Co., Ltd.). 95 vol% of the mixture which would be crosslinked later to become a matrixmaterial was kneaded with 5 vol % of β-cyclodextrin (Dexy Pearl β-100 ofBio Research Corporation of Yokohama) as a water-soluble substance by adouble-screw extruder. Thereafter, dicumyl peroxide (Percumyl D40 of NOFCorporation) was added to the kneaded product in an amount of 0.4 partby mass based on 100 parts by mass of the total of 1,2-polybutadiene,polystyrene and P-cyclodextrin and further kneaded, and a crosslinkingreaction was carried out in a metal mold for insert molding having abovelight transmitting member at 170° C. for 10 minutes to mold an abrasivesubstrate having a diameter of 820 mm. A 59.4 mm×21.0 mm rectangularhole was made at a position 195 mm away from the center of the moldedproduct as shown in FIG. 27.

[0230] (2) Kneading of Light Transmitting Member Material

[0231] 98 volt of 1,2-polybutadiene (JSR RB830 of JSR Corporation) whichwould be crosslinked later to become a matrix material and 2 vol % ofβ-cyclodextrin (Dexy Pearl P-100 of Bio Research Corporation ofYokohama) as a water-soluble substance were kneaded together by adouble-screw extruder heated at 160° C. Thereafter, dicumyl peroxide(Percumyl D40 of NOF Corporation) was added to the kneaded product in anamount of 0.3 part by mass based on 100 parts by mass of the total of1,2-polybutadiene and β-cyclodextrin and further kneaded.

[0232] (3) Manufacture of Abrasive Pad

[0233] The abrasive pad substrate manufactured in (1) above was set ontothe projection portion (721) of the metal mold for insert molding asshown in FIG. 17 to ensure that the hole of the abrasive substratemanufactured in (1) above was situated at a position corresponding tothe light transmitting member.

[0234] Further, the light transmitting member material kneaded in (2)above was injected into the space above the projection portion in thecavity of the metal mold. The metal mold (71) was then fastened, and acrosslinking reaction was carried out at 170° C. for 18 minutes to moldan abrasive pad having a diameter of 820 mm in which the rear surface ofthe light transmitting member was recessed from the rear surface of theabrasive pad substrate.

[0235] The top surface of the projection portion (721) of the metal moldused in this example was a mirror finish surface.

[0236] (4) Evaluation of Abrasive Pad

[0237] This abrasive pad had a Shore D hardness of 65 and a tensileresidual elongation of 2%.

[0238] As described above, optical end-point detection can be carriedout without reducing polishing efficiency when the abrasive pad of thepresent invention is used. Not only the polishing end point but also allthe polishing states can be optically monitored. During the use of theabrasive pad, slurry does not leak to the rear side of the abrasive pad.

[0239] When at least part of the water-insoluble matrix material of thelight transmitting member is a crosslinked polymer, it is possible toprevent pores from being filled at the time of polishing and dressing.It is also possible to prevent the surface of the abrasive pad frombeing fluffed excessively. Therefore, the retainability of the slurry ishigh at the time of polishing, the retainability of the slurry can beeasily recovered by dressing, and scratching can be prevented.

[0240] When the crosslinked polymer for forming the light transmittingmember is crosslinked 1,2-polybutadiene, the above effect can be fullyobtained and sufficiently high light transmission properties can beobtained by containing the above crosslinked polymer. The crosslinked1,2-polybutadiene is stable to a strong acid or strong alkali containedin many kinds of slurry and further has excellent durability as it israrely softened by water absorption.

[0241] By reducing the thickness of the light transmitting member, lighttransmission properties can be improved. When the materials for formingthe light transmitting member and the abrasive substrate are differentin type or when they are the same in type but different in ratio, as thematerials for forming the light transmitting member can be changed, itis possible to improve the light transmission properties of the lighttransmitting member as required.

[0242] Further, with the method of manufacturing an abrasive pad of thepresent invention, an abrasive pad having a complex shape can be easilymanufactured because a light transmitting member and an abrasivesubstrate are manufactured as an integrated unit by using a metal moldand slurry does not leak to the rear side because the light transmittingmember and the abrasive substrate are fused together.

[0243] The metal mold for insert molding of the present invention makesit easy to manufacture an abrasive pad comprising an abrasive substrateand a light transmitting member.

[0244] Optical end-point detection can be carried out without reducingpolishing efficiency when the abrasive laminated pad of the presentinvention is used. Not only the polishing end point but also all thepolishing states can be optically observed. The abrasive laminated padhas sufficiently high flexibility and suitable conformability to theunevenness of the surface to be polished.

[0245] Further, when the abrasive laminated pad has a fixing layer, itcan be fixed on a polishing machine easily and quickly. Since it haslight transmission properties, it does not impair the light transmissionproperties of the light transmitting member.

[0246] With the polishing method of the present invention, opticalend-point detection can be carried out without reducing polishingefficiency.

What is claimed is:
 1. An abrasive pad comprising an abrasive substratehaving a polishing surface and a light transmitting member which isfused to the abrasive substrate and comprises a water-insoluble matrixmaterial and a water-soluble substance dispersed in the water-insolublematrix material.
 2. The abrasive pad of claim 1, wherein at least partof the water-insoluble matrix material is a crosslinked polymer.
 3. Theabrasive pad of claim 2, wherein the crosslinked polymer is crosslinked1,2-polybutadiene.
 4. The abrasive pad of claim 1, wherein the lighttransmitting member is made thin in a direction perpendicular to thepolishing surface of the abrasive substrate.
 5. The abrasive pad ofclaim 1, wherein the materials of the light transmitting material andthe abrasive substrate differ from each other in type and/or ratio. 6.The abrasive pad of claim 1 which has a fixing layer for fixing theabrasive pad on a polishing machine, which is formed on the rear surfaceopposite to the polishing surface of the abrasive pad.
 7. A method ofmanufacturing the abrasive pad of claim 1, comprising holding apreviously formed light transmitting member for an abrasive pad at apredetermined position in the cavity of a metal mold for insert moldingand injecting the material of an abrasive substrate into the remainingspace in the cavity to fuse the light transmitting member to theabrasive substrate.
 8. A method of manufacturing the polishing pad ofclaim 1, comprising holding a previously formed abrasive substratehaving a hole for accepting a light transmitting member in the cavity ofa metal mold for insert molding and injecting the material of the lighttransmitting member into the hole for accepting the light transmittingmember to fuse the abrasive substrate to the light transmitting member.9. A metal mold for insert molding for the manufacture of the abrasivepad of claim 1, which has a projection portion(s) and/or a depressedportion(s) for holding a light transmitting member or an abrasivesubstrate for an abrasive pad in a cavity.
 10. An abrasive laminated padcomprising the abrasive pad of claim 1 and a base layer having lighttransmission properties formed on the rear surface opposite to thepolishing surface of the abrasive pad.
 11. An abrasive laminated padcomprising the abrasive pad of claim 1, a base layer formed on the rearsurface opposite to the polishing surface of the abrasive pad, and afixing layer for fixing the pad on a polishing machine, formed on theside opposite to the abrasive pad of the base layer.
 12. A method ofpolishing a semiconductor wafer with an abrasive pad, characterized inthat the abrasive pad of claim 1 or the abrasive laminated pad of claim10 or 11 is used, and the polishing end point of the semiconductor waferis detected by an optical end-point detection device through the lighttransmitting member of the abrasive pad or the abrasive laminated pad.